1. Field of Invention
The present invention relates generally to a heating and cooling apparatus, and more specifically a heating, ventilation, and air conditioning system for the air conditioning of the interior of a motor vehicle.
2. Related Technology
Heating, ventilation, and air conditioning systems (HVAC systems) typically include an air path for hot air streams and an air path for cold air streams within the HVAC air handling module. The hot and cold air streams are typically in fluid communication with a heating element and a cooling element respectively to heat or cool air as desired. More specifically, the airflow enters the HVAC system and travels through the cooling element and becomes the cold air stream. A portion of the airflow then travels along a second air path through a heating element in order to become the hot air stream.
The hot and cold air streams combine to form a third, mixed air stream that flows into the vehicle interior compartment. By controlling the hot and cold air streams, a vehicle occupant is able to control the temperature of the mixed air stream as it enters the vehicle interior compartment. More specifically, the vehicle occupant controls the amount of air flowing through each of the two paths in order to control the temperature of the hot or cold combined air stream entering the vehicle interior compartment.
Delivering air streams having the vehicle occupants desired temperature to designated areas of the vehicle requires mixing of hot air streams and cold air streams in precise proportions. Moreover, to deliver substantially consistent temperatures to the different sections of the vehicle, such as floor vents, panel vents, defroster vents, and door vents, the hot and cold air streams must be sufficiently mixed to avoid undesirable temperature gradients within the combined air stream.
In addition to sufficiently mixing air streams in an HVAC system, it is also desirable to minimize unwanted environmental conditions, such as noise, vibration, or harshness (NVH), caused by the air flowing through the HVAC system. The problem of NVH is especially problematic at the point in the HVAC system where the various air streams mix, due to turbulent flow caused by one of the first or second air streams flowing past the air delivery mechanism of the other air stream.
Therefore, it is desirable to provide an assembly that provides a substantial mixture of hot and cold air streams while minimizing the NVH caused by such mixture.